Journal of Nuclear Fuel Cycle and Waste Technology

This study has been carried out to look into the characteristics of an oxidative-dissolution of fission products (FP) co-dissolved with uranium (U) in a (NH4)2CO3-H2O2 carbonate solution. Simulated FP-oxides which contained 12 components have been added to the solution to examine their dissolution characteristics. It is found that H2O2 is an effective oxidant to minimize the oxidative-dissolution of FP. In the 0.5 M (NH4)2CO3-0.5 M H2O2 solution, some elements such as Re, Te, Cs and Mo seem to be dissolved together with U, while 98±2 % for Re and Te, 94±2 % for Cs, and 29±2 % for Mo are dissolved for 2 hours. It is revealed that dissolution rates of Re, Te and Cs are high (completely dissolved within 10∼20 minutes) due to their high solubility in the (NH4)2CO3 solution regardless of the addition of H2O2, and independent of the concentrations of Na2CO3 and H2O2. However, the dissolution ratio of Mo seems to be slightly increased with time and about 33 % for 4 hours, indicating a very slow dissolution rate and also independent of the (NH4)2CO3 concentration. It is found that the most important factor for the oxidative-dissolution of FP is the pH of the solution and an effective dissolution is achieved at a pH between 9∼10 in order to minimize the dissolution of FP.

Keywords

Oxidative-dissolution,Solubility,Carbonate solution. Oxidant,Fission products